Transforming growth factor-beta impairs postburn immunoglobulin productionby limiting B-cell proliferation, but not cellular synthesis

Background: Transforming growth factor-beta (TGF-beta) has been shown to be an inhibitor of immunoglobulin (Ig) synthesis and may contribute to decrea sed Ig synthesis after burn injury. This study investigated the relationshi p between TGF-beta and Ig synthesis after burn injury. Methods: Twenty-four BALB/c mice received either a 30% body surface area fu ll-thickness contact burn or no burn, Splenocytes were isolated 8 days afte r burn and were cultured with 0, 0.05 or 0.5 ng/mL TGF-beta, After culture, total IgG and total IgM were measured by enzyme-linked immunosorbent assay . The number of IgM-secreting cells per 10(5) cells was measured by enzyme- linked immunoabsorbent spot forming assay. Total IgM per IgM-secreting cell (pg/cell) was calculated, Results: Total IgG, IgM, IgM-secreting cells, and B-cell number after cultu re were decreased by burn injury, and the decrease was exacerbated by the p resence of TGF-beta, The total IgM per IgM-secreting cells, however, was si gnificantly increased by TGF-beta at 0.5 ng/mL, Conclusion: These data demonstrates that TGF-beta does not specifically imp air IgM secretion by committed IgM B cells but appears to decrease B-cell p roliferation or clonal expansion.